1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright 1998 Juniper Networks, Inc.
5 * All rights reserved.
6 * Copyright (c) 2002-2003 Networks Associates Technology, Inc.
7 * All rights reserved.
8 *
9 * Portions of this software was developed for the FreeBSD Project by
10 * ThinkSec AS and NAI Labs, the Security Research Division of Network
11 * Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035
12 * ("CBOSS"), as part of the DARPA CHATS research program.
13 *
14 * Redistribution and use in source and binary forms, with or without
15 * modification, are permitted provided that the following conditions
16 * are met:
17 * 1. Redistributions of source code must retain the above copyright
18 * notice, this list of conditions and the following disclaimer.
19 * 2. Redistributions in binary form must reproduce the above copyright
20 * notice, this list of conditions and the following disclaimer in the
21 * documentation and/or other materials provided with the distribution.
22 * 3. The name of the author may not be used to endorse or promote
23 * products derived from this software without specific prior written
24 * permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * SUCH DAMAGE.
37 */
38
39 #include <sys/cdefs.h>
40 __FBSDID("$FreeBSD: stable/12/lib/libpam/modules/pam_unix/pam_unix.c 326219 2017-11-26 02:00:33Z pfg $");
41
42 #include <sys/param.h>
43 #include <sys/socket.h>
44 #include <sys/time.h>
45 #include <netinet/in.h>
46 #include <arpa/inet.h>
47
48 #include <login_cap.h>
49 #include <netdb.h>
50 #include <pwd.h>
51 #include <stdlib.h>
52 #include <string.h>
53 #include <stdio.h>
54 #include <syslog.h>
55 #include <time.h>
56 #include <unistd.h>
57
58 #include <libutil.h>
59
60 #ifdef YP
61 #include <ypclnt.h>
62 #endif
63
64 #define PAM_SM_AUTH
65 #define PAM_SM_ACCOUNT
66 #define PAM_SM_PASSWORD
67
68 #include <security/pam_appl.h>
69 #include <security/pam_modules.h>
70 #include <security/pam_mod_misc.h>
71
72 #define PASSWORD_HASH "md5"
73 #define DEFAULT_WARN (2L * 7L * 86400L) /* Two weeks */
74 #define SALTSIZE 32
75
76 #define LOCKED_PREFIX "*LOCKED*"
77 #define LOCKED_PREFIX_LEN (sizeof(LOCKED_PREFIX) - 1)
78
79 static void makesalt(char []);
80
81 static char password_hash[] = PASSWORD_HASH;
82
83 #define PAM_OPT_LOCAL_PASS "local_pass"
84 #define PAM_OPT_NIS_PASS "nis_pass"
85
86 /*
87 * authentication management
88 */
89 PAM_EXTERN int
pam_sm_authenticate(pam_handle_t * pamh,int flags __unused,int argc __unused,const char * argv[]__unused)90 pam_sm_authenticate(pam_handle_t *pamh, int flags __unused,
91 int argc __unused, const char *argv[] __unused)
92 {
93 login_cap_t *lc;
94 struct passwd *pwd;
95 int retval;
96 const char *pass, *user, *realpw, *prompt;
97
98 if (openpam_get_option(pamh, PAM_OPT_AUTH_AS_SELF)) {
99 user = getlogin();
100 } else {
101 retval = pam_get_user(pamh, &user, NULL);
102 if (retval != PAM_SUCCESS)
103 return (retval);
104 }
105 pwd = getpwnam(user);
106
107 PAM_LOG("Got user: %s", user);
108
109 if (pwd != NULL) {
110 PAM_LOG("Doing real authentication");
111 realpw = pwd->pw_passwd;
112 if (realpw[0] == '\0') {
113 if (!(flags & PAM_DISALLOW_NULL_AUTHTOK) &&
114 openpam_get_option(pamh, PAM_OPT_NULLOK))
115 return (PAM_SUCCESS);
116 PAM_LOG("Password is empty, using fake password");
117 realpw = "*";
118 }
119 lc = login_getpwclass(pwd);
120 } else {
121 PAM_LOG("Doing dummy authentication");
122 realpw = "*";
123 lc = login_getclass(NULL);
124 }
125 prompt = login_getcapstr(lc, "passwd_prompt", NULL, NULL);
126 retval = pam_get_authtok(pamh, PAM_AUTHTOK, &pass, prompt);
127 login_close(lc);
128 if (retval != PAM_SUCCESS)
129 return (retval);
130 PAM_LOG("Got password");
131 if (strnlen(pass, _PASSWORD_LEN + 1) > _PASSWORD_LEN) {
132 PAM_LOG("Password is too long, using fake password");
133 realpw = "*";
134 }
135 if (strcmp(crypt(pass, realpw), realpw) == 0)
136 return (PAM_SUCCESS);
137
138 PAM_VERBOSE_ERROR("UNIX authentication refused");
139 return (PAM_AUTH_ERR);
140 }
141
142 PAM_EXTERN int
pam_sm_setcred(pam_handle_t * pamh __unused,int flags __unused,int argc __unused,const char * argv[]__unused)143 pam_sm_setcred(pam_handle_t *pamh __unused, int flags __unused,
144 int argc __unused, const char *argv[] __unused)
145 {
146
147 return (PAM_SUCCESS);
148 }
149
150 /*
151 * account management
152 */
153 PAM_EXTERN int
pam_sm_acct_mgmt(pam_handle_t * pamh,int flags __unused,int argc __unused,const char * argv[]__unused)154 pam_sm_acct_mgmt(pam_handle_t *pamh, int flags __unused,
155 int argc __unused, const char *argv[] __unused)
156 {
157 struct addrinfo hints, *res;
158 struct passwd *pwd;
159 struct timeval tp;
160 login_cap_t *lc;
161 time_t warntime;
162 int retval;
163 const char *user;
164 const void *rhost, *tty;
165 char rhostip[MAXHOSTNAMELEN] = "";
166
167 retval = pam_get_user(pamh, &user, NULL);
168 if (retval != PAM_SUCCESS)
169 return (retval);
170
171 if (user == NULL || (pwd = getpwnam(user)) == NULL)
172 return (PAM_SERVICE_ERR);
173
174 PAM_LOG("Got user: %s", user);
175
176 retval = pam_get_item(pamh, PAM_RHOST, &rhost);
177 if (retval != PAM_SUCCESS)
178 return (retval);
179
180 retval = pam_get_item(pamh, PAM_TTY, &tty);
181 if (retval != PAM_SUCCESS)
182 return (retval);
183
184 if (*pwd->pw_passwd == '\0' &&
185 (flags & PAM_DISALLOW_NULL_AUTHTOK) != 0)
186 return (PAM_NEW_AUTHTOK_REQD);
187
188 if (strncmp(pwd->pw_passwd, LOCKED_PREFIX, LOCKED_PREFIX_LEN) == 0)
189 return (PAM_AUTH_ERR);
190
191 lc = login_getpwclass(pwd);
192 if (lc == NULL) {
193 PAM_LOG("Unable to get login class for user %s", user);
194 return (PAM_SERVICE_ERR);
195 }
196
197 PAM_LOG("Got login_cap");
198
199 if (pwd->pw_change || pwd->pw_expire)
200 gettimeofday(&tp, NULL);
201
202 /*
203 * Check pw_expire before pw_change - no point in letting the
204 * user change the password on an expired account.
205 */
206
207 if (pwd->pw_expire) {
208 warntime = login_getcaptime(lc, "warnexpire",
209 DEFAULT_WARN, DEFAULT_WARN);
210 if (tp.tv_sec >= pwd->pw_expire) {
211 login_close(lc);
212 return (PAM_ACCT_EXPIRED);
213 } else if (pwd->pw_expire - tp.tv_sec < warntime &&
214 (flags & PAM_SILENT) == 0) {
215 pam_error(pamh, "Warning: your account expires on %s",
216 ctime(&pwd->pw_expire));
217 }
218 }
219
220 retval = PAM_SUCCESS;
221 if (pwd->pw_change) {
222 warntime = login_getcaptime(lc, "warnpassword",
223 DEFAULT_WARN, DEFAULT_WARN);
224 if (tp.tv_sec >= pwd->pw_change) {
225 retval = PAM_NEW_AUTHTOK_REQD;
226 } else if (pwd->pw_change - tp.tv_sec < warntime &&
227 (flags & PAM_SILENT) == 0) {
228 pam_error(pamh, "Warning: your password expires on %s",
229 ctime(&pwd->pw_change));
230 }
231 }
232
233 /*
234 * From here on, we must leave retval untouched (unless we
235 * know we're going to fail), because we need to remember
236 * whether we're supposed to return PAM_SUCCESS or
237 * PAM_NEW_AUTHTOK_REQD.
238 */
239
240 if (rhost && *(const char *)rhost != '\0') {
241 memset(&hints, 0, sizeof(hints));
242 hints.ai_family = AF_UNSPEC;
243 if (getaddrinfo(rhost, NULL, &hints, &res) == 0) {
244 getnameinfo(res->ai_addr, res->ai_addrlen,
245 rhostip, sizeof(rhostip), NULL, 0,
246 NI_NUMERICHOST);
247 }
248 if (res != NULL)
249 freeaddrinfo(res);
250 }
251
252 /*
253 * Check host / tty / time-of-day restrictions
254 */
255
256 if (!auth_hostok(lc, rhost, rhostip) ||
257 !auth_ttyok(lc, tty) ||
258 !auth_timeok(lc, time(NULL)))
259 retval = PAM_AUTH_ERR;
260
261 login_close(lc);
262
263 return (retval);
264 }
265
266 /*
267 * password management
268 *
269 * standard Unix and NIS password changing
270 */
271 PAM_EXTERN int
pam_sm_chauthtok(pam_handle_t * pamh,int flags,int argc __unused,const char * argv[]__unused)272 pam_sm_chauthtok(pam_handle_t *pamh, int flags,
273 int argc __unused, const char *argv[] __unused)
274 {
275 #ifdef YP
276 struct ypclnt *ypclnt;
277 const void *yp_domain, *yp_server;
278 #endif
279 char salt[SALTSIZE + 1];
280 login_cap_t *lc;
281 struct passwd *pwd, *old_pwd;
282 const char *user, *old_pass, *new_pass;
283 char *encrypted;
284 time_t passwordtime;
285 int pfd, tfd, retval;
286
287 if (openpam_get_option(pamh, PAM_OPT_AUTH_AS_SELF))
288 user = getlogin();
289 else {
290 retval = pam_get_user(pamh, &user, NULL);
291 if (retval != PAM_SUCCESS)
292 return (retval);
293 }
294 pwd = getpwnam(user);
295
296 if (pwd == NULL)
297 return (PAM_AUTHTOK_RECOVERY_ERR);
298
299 PAM_LOG("Got user: %s", user);
300
301 if (flags & PAM_PRELIM_CHECK) {
302
303 PAM_LOG("PRELIM round");
304
305 if (getuid() == 0 &&
306 (pwd->pw_fields & _PWF_SOURCE) == _PWF_FILES)
307 /* root doesn't need the old password */
308 return (pam_set_item(pamh, PAM_OLDAUTHTOK, ""));
309 #ifdef YP
310 if (getuid() == 0 &&
311 (pwd->pw_fields & _PWF_SOURCE) == _PWF_NIS) {
312
313 yp_domain = yp_server = NULL;
314 (void)pam_get_data(pamh, "yp_domain", &yp_domain);
315 (void)pam_get_data(pamh, "yp_server", &yp_server);
316
317 ypclnt = ypclnt_new(yp_domain, "passwd.byname", yp_server);
318 if (ypclnt == NULL)
319 return (PAM_BUF_ERR);
320
321 if (ypclnt_connect(ypclnt) == -1) {
322 ypclnt_free(ypclnt);
323 return (PAM_SERVICE_ERR);
324 }
325
326 retval = ypclnt_havepasswdd(ypclnt);
327 ypclnt_free(ypclnt);
328 if (retval == 1)
329 return (pam_set_item(pamh, PAM_OLDAUTHTOK, ""));
330 else if (retval == -1)
331 return (PAM_SERVICE_ERR);
332 }
333 #endif
334 if (pwd->pw_passwd[0] == '\0'
335 && openpam_get_option(pamh, PAM_OPT_NULLOK)) {
336 /*
337 * No password case. XXX Are we giving too much away
338 * by not prompting for a password?
339 * XXX check PAM_DISALLOW_NULL_AUTHTOK
340 */
341 old_pass = "";
342 retval = PAM_SUCCESS;
343 } else {
344 retval = pam_get_authtok(pamh,
345 PAM_OLDAUTHTOK, &old_pass, NULL);
346 if (retval != PAM_SUCCESS)
347 return (retval);
348 }
349 PAM_LOG("Got old password");
350 /* always encrypt first */
351 encrypted = crypt(old_pass, pwd->pw_passwd);
352 if (old_pass[0] == '\0' &&
353 !openpam_get_option(pamh, PAM_OPT_NULLOK))
354 return (PAM_PERM_DENIED);
355 if (strcmp(encrypted, pwd->pw_passwd) != 0)
356 return (PAM_PERM_DENIED);
357 }
358 else if (flags & PAM_UPDATE_AUTHTOK) {
359 PAM_LOG("UPDATE round");
360
361 retval = pam_get_authtok(pamh,
362 PAM_OLDAUTHTOK, &old_pass, NULL);
363 if (retval != PAM_SUCCESS)
364 return (retval);
365 PAM_LOG("Got old password");
366
367 /* get new password */
368 for (;;) {
369 retval = pam_get_authtok(pamh,
370 PAM_AUTHTOK, &new_pass, NULL);
371 if (retval != PAM_TRY_AGAIN)
372 break;
373 pam_error(pamh, "Mismatch; try again, EOF to quit.");
374 }
375 PAM_LOG("Got new password");
376 if (retval != PAM_SUCCESS) {
377 PAM_VERBOSE_ERROR("Unable to get new password");
378 return (retval);
379 }
380
381 if (getuid() != 0 && new_pass[0] == '\0' &&
382 !openpam_get_option(pamh, PAM_OPT_NULLOK))
383 return (PAM_PERM_DENIED);
384
385 if ((old_pwd = pw_dup(pwd)) == NULL)
386 return (PAM_BUF_ERR);
387
388 lc = login_getclass(pwd->pw_class);
389 if (login_setcryptfmt(lc, password_hash, NULL) == NULL)
390 openpam_log(PAM_LOG_ERROR,
391 "can't set password cipher, relying on default");
392
393 /* set password expiry date */
394 pwd->pw_change = 0;
395 passwordtime = login_getcaptime(lc, "passwordtime", 0, 0);
396 if (passwordtime > 0)
397 pwd->pw_change = time(NULL) + passwordtime;
398
399 login_close(lc);
400 makesalt(salt);
401 pwd->pw_passwd = crypt(new_pass, salt);
402 #ifdef YP
403 switch (old_pwd->pw_fields & _PWF_SOURCE) {
404 case _PWF_FILES:
405 #endif
406 retval = PAM_SERVICE_ERR;
407 if (pw_init(NULL, NULL))
408 openpam_log(PAM_LOG_ERROR, "pw_init() failed");
409 else if ((pfd = pw_lock()) == -1)
410 openpam_log(PAM_LOG_ERROR, "pw_lock() failed");
411 else if ((tfd = pw_tmp(-1)) == -1)
412 openpam_log(PAM_LOG_ERROR, "pw_tmp() failed");
413 else if (pw_copy(pfd, tfd, pwd, old_pwd) == -1)
414 openpam_log(PAM_LOG_ERROR, "pw_copy() failed");
415 else if (pw_mkdb(pwd->pw_name) == -1)
416 openpam_log(PAM_LOG_ERROR, "pw_mkdb() failed");
417 else
418 retval = PAM_SUCCESS;
419 pw_fini();
420 #ifdef YP
421 break;
422 case _PWF_NIS:
423 yp_domain = yp_server = NULL;
424 (void)pam_get_data(pamh, "yp_domain", &yp_domain);
425 (void)pam_get_data(pamh, "yp_server", &yp_server);
426 ypclnt = ypclnt_new(yp_domain,
427 "passwd.byname", yp_server);
428 if (ypclnt == NULL) {
429 retval = PAM_BUF_ERR;
430 } else if (ypclnt_connect(ypclnt) == -1 ||
431 ypclnt_passwd(ypclnt, pwd, old_pass) == -1) {
432 openpam_log(PAM_LOG_ERROR, "%s", ypclnt->error);
433 retval = PAM_SERVICE_ERR;
434 } else {
435 retval = PAM_SUCCESS;
436 }
437 ypclnt_free(ypclnt);
438 break;
439 default:
440 openpam_log(PAM_LOG_ERROR, "unsupported source 0x%x",
441 pwd->pw_fields & _PWF_SOURCE);
442 retval = PAM_SERVICE_ERR;
443 }
444 #endif
445 free(old_pwd);
446 }
447 else {
448 /* Very bad juju */
449 retval = PAM_ABORT;
450 PAM_LOG("Illegal 'flags'");
451 }
452
453 return (retval);
454 }
455
456 /* Mostly stolen from passwd(1)'s local_passwd.c - markm */
457
458 static unsigned char itoa64[] = /* 0 ... 63 => ascii - 64 */
459 "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
460
461 static void
to64(char * s,long v,int n)462 to64(char *s, long v, int n)
463 {
464 while (--n >= 0) {
465 *s++ = itoa64[v&0x3f];
466 v >>= 6;
467 }
468 }
469
470 /* Salt suitable for traditional DES and MD5 */
471 static void
makesalt(char salt[SALTSIZE+1])472 makesalt(char salt[SALTSIZE + 1])
473 {
474 int i;
475
476 /* These are not really random numbers, they are just
477 * numbers that change to thwart construction of a
478 * dictionary.
479 */
480 for (i = 0; i < SALTSIZE; i += 4)
481 to64(&salt[i], arc4random(), 4);
482 salt[SALTSIZE] = '\0';
483 }
484
485 PAM_MODULE_ENTRY("pam_unix");
486